(CBS/AP) BOSTON - Nearly 200 inmates have been released from prison and their cases put on hold after a chemist at a Massachusetts state drug testing lab was accused of faking results.

Public Safety Secretary Mary Beth Heffernan told lawmakers at a public hearing Wednesday that while investigators are looking at about 34,000 cases overall, 195 individuals have been released, including 79 in Boston.

Heffernan said their release doesn't mean they have been exonerated. She didn't say what kinds of crimes they had been convicted of, but said they could be under alternative forms of supervision as they await future court hearings to resolve their cases.

A handful of those released have since been re-arrested.

Heffernan said the administration is "committed to ensuring that each individual's case is reviewed completely to ensure that justice has been administered properly."

On Tuesday, officials said Gov. Deval Patrick has ordered a "file-by-file review" of every case handled by the chemist, Annie Dookhan, who investigators said manipulated drug samples at a former Department of Public Health drug lab where she worked for nine years.

The drug testing lab, which was overseen by the Department of Public Health, has since been closed. It's testing has been turned over to the state police.

Massachusetts Attorney General Martha Coakley's office is conducting a criminal investigation, while state Inspector General Glenn Cunha is reviewing whether the problems at the lab went beyond Dookhan and her immediate supervisor.

David Meier, a former state prosecutor appointed by Patrick to identify cases Dookhan worked on, said Tuesday that his team has identified about 10,000 people whose drug cases were potentially affected by the alleged misconduct.